Coaxial connector

ABSTRACT

This invention relates to a simple, field installable, low cost, miniature, push-pull, quick connect/disconnect electrical connector system having a VSWR (voltage standing wave ratio) of less than 1.35 for all signal frequencies from 0.1 to 6 GHz useful for interconnecting coaxial cables having a characteristic impedance in the range of 50 ohms. The connector system is made up of a plug member and a jack member each comprising but three basic parts. The first part of each member is comprised of an integral tubular member of relatively soft electrically conductive material. The second part of each member is in turn comprised of a dielectric insert which is held in its respective tubular member by staking or rolling a reduced section of its tubular member&#39;&#39;s wall. The front portion of the jack member fits into the front portion of the plug member and through the action of an internal shoulder within the plug member a predetermined spacing between the dielectric inserts held by the plug and jack members is established when the members are fully mated. Each dielectric insert is in turn bored to receive one of two matable pin-like electrical contacts each of which comprises the third part of its respective connector member. Each contact has a hollow rear portion which may be crimped to the center conductor of a respective coaxial cable and thereafter inserted into the bore of its respective insert and retained therein. The outer conductor of each coaxial cable may be crimped around a reduced section of the rear portion of each connector by means of a crimping ferrule. The aforesaid fixed spacing between the dielectric inserts acts to produce a high impedance relative to the impedance afforded by the dielectric inserts to effect the afore-referenced VSWR of less than 1.35 for signal frequencies between 0.1 and 6 GHz.

United States Patent [191 Sladek et a1.

Aug. 6, 1974 COAXIAL CONNECTOR [75] lnventors: Norbert J. Sladek,Fairficld;

Pasquale Ralph Petti, Waterbury; William Max Erich Zerlin, Newtown, allof Conn.

[73] Assignee: Bunker Ramo Corporation, Oak

Brook, Ill.

[22] Filed: Sept. 28, 1972 [2]] Appl. No.: 292,856

[52] US. Cl. 339/177 R, 333/33 [51] Int. Cl H0lr 17/12 [58] Field ofSearch 333/33; 339/177 [56] References Cited UNITED STATES PATENTS2,449,073 9/1948 Johannesen 339/l77 R X 3,076,169 l/l963 Blaisdell..339/177 R X 3,390,374 6/1968 Forney 339/177 R 3,460,072 8/1969 Ziegler333/33 3,564,478 2/1971 Hampton 339/217 S X 3,566,334 Z/l97l Ziegler339/177 R 3,639,889 2/1972 Komadina 339/177 ET OTHER PUBLICATIONSElectro-Technology, Burndy Connectors December, 1962, page 183, copy in339-177 R.

Primary Examiner-Francis K. Zugel Assistant Examiner-Lawrence J. StaabAttorney, Agent, or FirmD. R. Bair; R. J. Kransdorf; F. M. Arbuckle [57]ABSTRACT This invention relates to a simple, field installable, low

cost, miniature, push-pull, quick connect/disconnect electricalconnector system having a VSWR (voltage standing wave ratio) of lessthan 1.35 for all signal fre' quencies from 0.1 to 6 GHz useful forinterconnecting coaxial cables having a characteristic impedance in therange of 50 ohms. The connector system is made up of a plug member and ajack member each comprising but three basic parts. The first part ofeach member is comprised of an integral tubular member of relativelysoft electrically conductive material. The second part of each member isin turn comprised of a dielectric insert which is held in its respectivetubular member by staking or rolling a reduced section of its tubularmembers wall. The front portion of the jack member fits into the frontportion of the plug member and through the action of an internalshoulder within the plug member a predetermined spacing between thedielectric inserts held by the plug and jack members is established whenthe members are fully mated. Each dielectric insert is in turn bored toreceive one of two matable pin-like electrical contacts each of whichcomprises the third part of its respective connector member. Eachcontact has a hollow rear portion which may be crimped to the centerconductor of a respective coaxial cable and thereafter inserted into thebore of its respective insert and retained therein. The outer conductorof each coaxial cable may be crimped around a reduced section of therear portion of each connector by means of a crimping ferrule. Theaforesaid fixed spacing between the dielectric inserts acts to produce ahigh impedance relative to the impedance afforded by the dielectricinserts to effect the afore-referenced VSWR of less than 1.35 for signalfrequencies between 0.1 and 6 GHz.

7 Claims, 6 Drawing Figures COAXIAL CONNECTOR This invention relates toan electrical connector adapted for mating a pair of coaxial cables andmore particularly to an inexpensive quick connect/disconnect coaxialconnector with minimum reflections (and thus low voltage standing waveratio, VSWR) at frequencies up to six GHz.

BACKGROUND OF THE INVENTION The characteristic impedance of a coaxialtransmission line is normally about 50 ohms. In order to avoid impedancemismatches, the impedance through all sections of a connector joiningtwo coaxial lines should thus also be substantially 50 ohms. Whereimpedance mismatches do occur through sections of a coaxial connector,reflections may occur, adversely effecting the voltage standing waveratio (VSWR) of the connector and resulting in attenuation of any signalpassing through the connector. The attenuation caused by an impedancemismatch increases significantly as the frequency of the line signalincreases. Thus, an impedance mismatch which may be acceptable in aconnector intended for low frequency applications, becomes unacceptablewhen an attempt is made to utilize the connector with higher frequencylines.

Heretofore, the requirement of obtaining a substantially uniform 50 ohmimpedance through a coaxial connector has required fairly careful designand manufacture. The resulting connector has therefore been relativelyexpensive. Lower cost connectors, such as standard phono-connectors,have heretofore been limited to applications with line frequencies nogreater than 0.5 GHZ. However, even these phone-connectors arerelatively expensive, and in applications such as in mobile radio wherefrequencies above 0.5 GHz are utilized, these connectors are clearlyinadequate.

A need therefore exists for a simple, inexpensive radio frequencycoaxial connector which provides minimum reflections and thus acceptableVSWR and performance at frequencies up to six GHz. Normally, a connectorwill be considered to have acceptable VSWR and performance if VSWR isless than 1.35 over the entire frequency range that the connector isintended to operate in (for example, 0.1 to 6 GHz). Such a connectorshould also provide for quick connect and disconnect, while stillproviding reliable mating.

SUMMARY OF THE INVENTION This invention therefore provides an electricalconnector adapted for mating a pair of coaxial lines which connectorincludes a plug and a jack. The plug has a male center contact, acylindrical outer contact projecting beyond the center contact andhaving at least one tine biased toward the center of the contact, and aninsert of an insulating material mounted in the outer contact and havingan axial opening in which the center contact is supported. The jack hasa female center contact dimensioned to have the male contact fit snuglytherein, a cylindrical outer contact dimensioned to fit into the plugouter contact with the tine in pressure engagement with the outer wallthereof, and an insert of insulating material mounted in the outercontact and have an axial opening in which the center contact issupported. The plug and jack are dimensioned to provide a small air gapbetween their inserts of insulating material when the plug and jack arefully mated.

The impedance of the air gap is slightly greater than the characteristicimpedance of the lines while the impedance of the inserts are slightlyless than the characteristic impedance of the lines. This results in thevector sum of the reflections due to the insert and gap inpedances in amated connector pair being very small (i.e., a VSWR of less than 1.35).The balancing of impedance mismatches in conjunction with the minimizingof the length of the impedance mismatch area permits an inexpensiveconnector to be provided which connector achieves the requiredperformance parameters.

' The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention as illustrated inthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional side view of theplug portion of v a connector of a preferred embodiment of theinvention.

FIG. 2 is a front view of the plug shown in FIG. 1.

FIG. 3 is a sectional side view of the jack portion of a connector of apreferred embodiment of the invention.

FIG. 4 is a front view of the jack shown in FIG. 3

FIG. 5 is a sectional side view of the connector of the preferredembodiment of the invention showing the plug and jack in a matedcondition.

FIG. 6A is a sectional side view of the center contact portion of thejack for an alternative embodiment of the invention.

FIG. 6B is a portional sectional side view of the center contact portionof the plug for the embodiment of the invention shown in FIG. 6A.

DETAILED DESCRIPTION Referring now to FIGs.,1 and 2, it is seen that theplug 10 for the connector of a preferred embodiment of the inventionconsists of a one-piece tubular body member 12 of a conducting material,an insert 14 of an insulating material staked at four places 16 (onlytwo of which are shown in FIG. 1) near the center of body 12, and acenter contact 18 of a conducting material supported in an axial bore 20formed through insert 14. The forward or contact portion 22 of body 12is slotted to provide a pair of upper and lower sections each of whichextends for approximately and a pair of tines 26 which are each biasedtoward the center of body. The leading surface of each section 24 andtine 26 is slightly flared to assist in the insertion of a mating jack.The rear portion 28 of body 12 is tapered and, as may be seen in FIG. 5,is adapted to fit between the outer conductor 32 and insulator 30 of acoaxial cable or line 34. Portion 28 has a bore 36 sized to accept thecable insulation 35. Bore 36 terminates in a counterbore ,38 in which ispositioned insert 14. Counterbore 38 terminates in a second counterbore40 in the outer contact region 22 of the body. A shoulder 42, thefunction of which will be described later, is formed at the juctionbetween counterbores 38 and 40. A crimp ferrule 44 is provided to secureouter conductor 32 of the cable to portion 28 of body 12.

Center contact 18 has a rear opening 46 in which center conductor 48 ofcable 34 is either soldered or crimped. The center contact is thenpassed through the rear of the connector and forced through opening 20to position the contact as shown. A barb 49 is formed near the center ofcontact 18 to prevent the contact from being withdrawn once it has beenso positioned (i.e., to captivate the contact in the connector). Theforward contact portion 50 of the contact 18 has a tapered bullet-shapedleading edge for easy insertion into a mating female contact and is, asbest seen in FIG. 2, cross-slotted. This permits the contact to compressslightly when being inserted into a mating female contact to providegood pressure contact therewith.

Jack 52 (FIGS. 3 and 4) also has a one-piece body 54, an insulatinginsert 56, a center contact 58 and a crimp ferrule 60. Body 54 has acylindrical forward contact portion 62 with a tapered leading surfacefor insertion into contact portion 22 of plug and an extending rear orferrule portion 64 with a tapered trailing edge which, as is seen inFIG. 5, is adapted to be fitted between the insulation and outerconductor of a coaxial cable 34. Body 54 also has a bore 66 with anenlarged counterbore 68 in its forward portion. Insert 56 is positionedin the rear of counterbore 68 and is held therein by being staked atfour points 70 (only two of which are shown in FIG. 3). Insert 56 has anaxial bore 72 in which is supported center contact 58. Center contact 58is in the form of a hollow tube having a pair of pierced tabs 74 whichserve to captivate the contact in the jack once the contact has beenpassed through the rear of insert 56. As with the plug, center conductor48 of the cable is secured in contact 58 by either soldering or crimpingand outer conductor 32 is secured to portion 64 of body 54 by crimpingferrule 60 over the outer conductor in standard fashion.

All parts of plug 10 and jack 52 are of a conductive material such asbrass except inserts l4 and 56 which are of an insulating material suchas polytetrafluoroethylene (also known by the trademark Teflon). Thebrass parts may be coated with nickel to reduce corrosion.

Referring now to FIG. 5, it is seen that when the parts are fullyassembled, the leading edge of jack outer contact 62 bottoms on shoulder42 of plug 10. This leaves an air gap 76 in the mated connectors betweeninsert 56 and insert 14 which is equal to the width of counterbores 68and 38 not filled by the respective inserts. For preferred embodimentsof the invention, the insert fills about 60 percent of the counterboreand the air gap the remaining 40 percent. However, since the totallength of each counterbore, for the preferred embodiment of theinvention, is less than a quarter of an inch, the total length of theimpedance mismatch is relatively short. The impedance of the air sectionis roughly 62 ohms and the impedance of the insert section (assumingTeflon as the insert material) is roughly 44 ohms. As a result, thevector summation of the reflections through the mismatch area is small,the reflections introduced in one mismatched section tending cancelthose introduced in the other mismatched section with little substantialnet adverse effect resulting on the applied signal. Connectors builtutilizing the design described above have been found to have a VSWR ofless than 1.20 (in most instances less than 1.15) over a frequency rangefrom 0.1 to 6 GHz. Thus, these connectors are, in accordance withstandards previously mentioned, adapted for providing acceptableperformance at frequencies up to six GHz.

FIGS. 6A and 6B illustrate the center contact portions of a jack andplug respectively of an alternative embodiment of the invention. Femalecenter contact 80 of the jack 54 for the alternative embodiment of theinvention, is machined from rod stock rather than being a hollow tube.This contact has a rear opening 82 formed in it which is adapted to havethe center conductor 48 of a coaxial cable 34 secured therein in thesame manner that a conductor is secured in opening 46 of contact 18.Contact 80 also has a forward opening 84 which is slotted so as to beadapted for expansion, and a barb or ring 86 formed around itscircumference which barb is identical to and performs the same functionsas barb 49. In the alternative, barb 86 may be of reduced size andpositioned further back on contact 80 so that it remains within insert56 when the contact is properly positioned. With either configuration,the barb tends to hold the contact against movement in jack 54.

The center contact 88 of plug 12' is identical to center contact 18 ofplug 12 (FIG. 1) except that forward contact portion 90 is in the shapeof a solid tapered bullet rather than a slotted tapered bullet. Contactportion 90 is sized so as to cause a slight expansion of opening 84 whencontact portion 90 is fitted therein assuring a good pressure fitbetween contacts 80 and 88.

The connectors described above are adapted to be quickly connected bymerely pushing the plug and jack together and to be quickly disconnectedby pulling these two elements apart. No predetermined orientation ofparts, screwing, clamping, or other operations are required. Tines 26being in pressure contact with the outer wall of contact area 62 of jack52 assure a good physical and electrical connection of the outerconductors while the compression of slotted bullet contact 50 onentering tubular contact 58 or the expansion of slotted contact 80 whencontact 88 enters it assures good physical and electrical contact underpressfi of the inner contacts There is a wiping action on both the innerand outer conductors during connect and disconnect which removescontaminents and further assures good electrical contact. Barb 49 andtabs 74 or barb 86 restrict movement of their center contacts in theconnectors to within about 16 mils minimizing the adverse VSWR effectsof such movement.

Since the plug and the jack of the connector of this invention have onlythree parts each, plus a crimp ferrule, which parts are assembled usingsimple and straightforward techniques, both the material and assemblycosts for the connector of this invention are minimized. An extremelylow cost, simple, quick connect/disconnect, high perfonnance RF coaxialconnector has thus been provided.

While the description above has been with reference to preferredembodiments of the invention, it is apparent that some modifications inthe details of the design may be made. For example, the number of tines26 may be varied from as little as one to as many as four or five.Similarly, a single cut rather than a crosscut may be utilized for thetip 50 of contact 18. Thus, while the invention has been shown anddescribed above with reference to preferred embodiments, the foregoingand other modifications may be made in the connector of this inventionby those skilled in the art while still remaining within the spirit andscope of the invention.

What is claimed is:

1. An improved low cost quick connect/disconnect electrical connectorhaving a VSWR of less than 1.35 for all signal frequencies from 0.1 to 6GHz, including a plug member and a jack member which, when in axialalignment with one another, may be pushed together or pulled apart tointerconnect or disconnect two coaxial cables each of substantially thesame characteristic impedance, the coaxial cables having an innerconductor and an outer conductor separated by a body of dielectricmaterial, said plug member comprising a first, a second and a third plugparts;

said first plug part having a front, central and rear axially extendingportions contiguous with one another and being formed of an integraltubular body of relatively soft resilient electrically conductivematerial, said tubular body having an axial bore extending through therear portion thereof, said bore having an internal diametersubstantially equal to the outer diameter of the dielectric body of onecoaxial cable to permit said dielectric body to be snugly receivedwithin the rear portion of said tubular body, a section of said rearportion of said body contiguous with the rear extremity thereof beingreduced sufficiently to accept a crimping ferrule for holding the outerconductor of said coaxial cable against the outer periphery of saidreduced rear seciton and to form an external laterally extendingshoulder against which a crimping ferrule may be longitudinally seatedand restrained from axial movement toward the front portion of saidtubular body;

said tubular body having a first counterbore extending through thecentral portion thereof, said first counterborehaving an internaldiameter greater than said bore in said rear portion to form a firstinternal laterally extending shoulder located at the rear extremity ofsaid first counterbore and the front extremity of said bore, at least aportion of said central portion being reduced on its outer peripherynear said rear portion to form a first wall of Y said relatively softmaterial which is defined between the inner surface ,of said firstcounterbore and the outer surface of said reduced central portion andwhich is inwardly deformable by externally staking or rolling said wall;

said tubular body having a second counterbore extending through thefront portion thereof, said second counterbore having a diameter largerthan said first counterbore to form a second internal laterallyextending shoulder located at the rear extremity of said secondcounterbore and the front extremity of said first counterbore againstwhich the front extremity of a jack member may abut when said plug andsaid jack member are pushed together and mated, the internal diameter ofsaid second counterbore and the external diameter of said front portionforming a resilient second wall of said conductive materiallongitudinally slit and formed to grip said jack member when insertedtherein by spring action;

said second plug part comprising a cylindrical insert of resilientdielectric material having a diameter substantially equal to that of thefirst counterbore of said first plug part and positioned within thecentral portion of said first plug part against said first internallaterally extending shoulder, said insert having a length less than theaxial length of said first plug part central portion and retainedtherein by deformation of said first wall into gripping relation withthe outer periphery of said insert, said insert having a central borefor receiving said third plug part;

said third plug part comprising an electrically conthe jack member ofsaid connector system comprising a first, second and third jack parts;

said first jack having a front and a rear axially extending portionscontiguous with one another and being formed of an integral tubular bodyof relatively soft resilient electrically conductive material, saidtubular body having an axial bore extending through the rear portionthereof, said bore having an internal diameter substantially equal tothe outer diameter of the dielectric body of another coaxial cable topermit said dielectric body to be snugly received within the rearportion of said tubular body, a section of said rear portion of saidbody contiguous with the rear extremity thereof being reducedsufficiently to accept a crimping ferrule for holding the outerconductor of said coaxial cable against the outer periphery of saidreduced rear section and to form an external laterally extendingshoulder against which a crimping ferrule may be longitudinally seatedand restrained from axial movement toward the front portion of saidbody;

said tubular body having a counterbore extending through the frontportion thereof, said counterbore having an internal diameter greaterthan said rear portion bore to form a first internal laterally extendingshoulder located at the rear extremity of said counterbore and the frontextremity of said bore, at least a portion of said front portion beingreduced on its outer periphery near said rear end portion to form afirst wall of said relatively soft material which is defined between theinner surface of said counterbore and the outer surface of said reducedfront portion and which is inwardly deformable by externally staking orrolling said wall;

said second jack part comprising a cylindrical insert said third jackpart comprising an electrically conductive contact member matable withthe contact member carried by said plug member and having a hollow rearportion for accepting and retaining the inner conductor of the other ofsaid coaxial cables and a front end portion formed to pass through fromthe rear of said first jack part and be axially restrained from rearwardmovement therein within the bore of said second jack part after theinner conductor of said coaxial cable has been retained in said hollowrear portion thereof, the spacing between the front surfaces of thedielectric inserts in said plug member and said jack member when saidmembers are mated forming an impedance which is greater than thecharacteristic impedance of said coaxial cables with the dielectricconstant of said inserts and the lengths thereof forming impedanceswhich are less than the characteristic impedance of said coaxial cableswhereby said plug member and said jack member when mated provide aconnector system having a VSWR of less than 1.35 for all signalfrequencies from 0.1 to 6 GHZ.

2. A connector system according to claim 1 wherein said second plug partand said second jack part have substantially the same dimensions.

3. A connector system according to claim 1 wherein said first wall ofsaid first jack part is substantially the same thickness as the depth ofsaid second internal laterally extending shoulder of said first plugpart with the outer diameter of a section of the front portion of saidfirst jack part being substantially equal to the inner diameter of thesecond counter-bore of said first plug part.

4. A connector system according to claim 1 wherein said front endportion of said electrically conductive contact retained by said plugmember extends beyond said second internal laterally extending shoulderwithin said first plug part but is contained substantially wholly withinsaid front portion of said first plug part and wherein the extremity ofsaid front end portion of said contact member carried by said secondjerk part extends beyond the front extremity of the dielectric insertforming said second jack part but is contained substantially whollywithin said front end portion of said first jack part.

5. A connector system according to claim 1 wherein the outer peripheryof said first jack part is provided with a tapered surface extendingrearwardly from the front extremity of the front portion thereof to aposition forward of the forward extremity of said second jack part toaid in the insertion thereof into the front portion of said first plugmember.

6. A connector system according to claim 1 wherein the characteristicimpedance of the coaxial cables to which said connector members are tointerconnect is substantially 50 ohms while the impedance formed by thespacing of said dielectric inserts are in the range of 62 ohms and theimpedance formed by each of said dielectric inserts is in the range of44 ohms.

7. A connector system according to claim 1 wherein the volume embracedbetween said dielectric inserts is substantially 40 per cent and thevolume occupied by said dielectric inserts is substantially per centrespectively of the total volume embraced within said connector systembetween said first internal shoulder of said first plug part and saidfirst internal shoulder of said first jack part when said plug and jackmember are fully mated.

1. An improved low cost quick connect/disconnect electrical connector having a VSWR of less than 1.35 for all signal frequencies from 0.1 to 6 GHz, including a plug member and a jack member which, when in axial alignment with one another, may be pushed together or pulled apart to interconnect or disconnect two coaxial cables each of substantially the same characteristic impedance, the coaxial cables having an inner conductor and an outer conductor separated by a body of dielectric material, said plug member comprising a first, a second and a third plug parts; said first plug part having a front, central and rear axially extending portions contiguous with one another and being formed of an integral tubular body of relatively soft resilient electrically conductive material, said tubular body having an axial bore extending through the rear portion thereof, said bore having an internal diameter substantially equal to the outer diameter of the dielectric body of one coaxial cable to permit said dielectric body to be snugly received within the rear portion of said tubular body, a section of said rear portion of said body contiguous with the rear extremity thereof being reduced sufficiently to accept a crimping ferrule for holding the outer conductor of said coaxial cable against the outer periphery of said reduced rear seciton and to form an external laterally extending shoulder against which a crimping ferrule may be longitudinally seated and restrained from axial movement toward the front portion of said tubular body; said tubular body having a first counterbore extending through the central portion thereof, said first counterbore having an internal diameter greater than said bore in said rear portion to form a first internal laterally extending shoulder located at the rear extremity of said first counterbore and the front extremity of said bore, at least a portion of said central portion being reduced on its outer periphery near said rear portion to form a first wall of said relatively soft material which is defined between the inner surface of said first counterbore and the outer surface of said reduced central portion and which is inwardly deformable by externally staking or rolling said wall; said tubular body having a second counterbore extending through the front portion thereof, said second counterbore having a diameter larger than said first counterbore to form a second internal laterally extending shoulder located at the rear extremity of said second counterbore and the front extremity of said first counterbore against which the front extremity of a jack member may abut when said plug and said jack member are pushed together and mated, the internal diameter of said second counterbore and the external diameter of said front portion forming a resilient second wall of said conductive material longitudinally slit and formed to grip said jack member when inserted therein by spring action; said second plug part comprising a cylindrical insert of resilient dielectric material having a diameter substantially equal to that of the first counterbore of said first plug part and positioned within the central portion of said first plug part against said first internal laterally extending shoulder, said insert having a length less than the axial length of said first plug part central portion and retained therein by deformation of said first wall into gripping relation with the outer periphery of said insert, said insert having a central bore for receiving said third plug part; said third plug part comprising an electrically conductive contact having a hollow rear portion for accepting and retaining the inner conductor of one of said coaxial cables and a front end portion formed to pass through from the rear of said firSt plug part and be axially restrained from rearward movement within the bore of said second plug part after the inner conductor of said coaxial cable has been retained in said hollow rear portion thereof; the jack member of said connector system comprising a first, second and third jack parts; said first jack having a front and a rear axially extending portions contiguous with one another and being formed of an integral tubular body of relatively soft resilient electrically conductive material, said tubular body having an axial bore extending through the rear portion thereof, said bore having an internal diameter substantially equal to the outer diameter of the dielectric body of another coaxial cable to permit said dielectric body to be snugly received within the rear portion of said tubular body, a section of said rear portion of said body contiguous with the rear extremity thereof being reduced sufficiently to accept a crimping ferrule for holding the outer conductor of said coaxial cable against the outer periphery of said reduced rear section and to form an external laterally extending shoulder against which a crimping ferrule may be longitudinally seated and restrained from axial movement toward the front portion of said body; said tubular body having a counterbore extending through the front portion thereof, said counterbore having an internal diameter greater than said rear portion bore to form a first internal laterally extending shoulder located at the rear extremity of said counterbore and the front extremity of said bore, at least a portion of said front portion being reduced on its outer periphery near said rear end portion to form a first wall of said relatively soft material which is defined between the inner surface of said counterbore and the outer surface of said reduced front portion and which is inwardly deformable by externally staking or rolling said wall; said second jack part comprising a cylindrical insert of resilient dielectric material having a diameter substantially equal to that of said first jack part counterbore and positioned within said counterbore against the laterally extending shoulder therein, said insert having a length less than the axial length of said first jack part front portion and retained therein by deformation of said wall into gripping relation with the outer periphery of said insert, said insert having a central bore for receiving said third jack part; said third jack part comprising an electrically conductive contact member matable with the contact member carried by said plug member and having a hollow rear portion for accepting and retaining the inner conductor of the other of said coaxial cables and a front end portion formed to pass through from the rear of said first jack part and be axially restrained from rearward movement therein within the bore of said second jack part after the inner conductor of said coaxial cable has been retained in said hollow rear portion thereof, the spacing between the front surfaces of the dielectric inserts in said plug member and said jack member when said members are mated forming an impedance which is greater than the characteristic impedance of said coaxial cables with the dielectric constant of said inserts and the lengths thereof forming impedances which are less than the characteristic impedance of said coaxial cables whereby said plug member and said jack member when mated provide a connector system having a VSWR of less than 1.35 for all signal frequencies from 0.1 to 6 GHz.
 2. A connector system according to claim 1 wherein said second plug part and said second jack part have substantially the same dimensions.
 3. A connector system according to claim 1 wherein said first wall of said first jack part is substantially the same thickness as the depth of said second internal laterally extending shoulder of said first plug part with the outer diameter of a section of the front portion of said first jack part being substantially equal to thE inner diameter of the second counterbore of said first plug part.
 4. A connector system according to claim 1 wherein said front end portion of said electrically conductive contact retained by said plug member extends beyond said second internal laterally extending shoulder within said first plug part but is contained substantially wholly within said front portion of said first plug part and wherein the extremity of said front end portion of said contact member carried by said second jerk part extends beyond the front extremity of the dielectric insert forming said second jack part but is contained substantially wholly within said front end portion of said first jack part.
 5. A connector system according to claim 1 wherein the outer periphery of said first jack part is provided with a tapered surface extending rearwardly from the front extremity of the front portion thereof to a position forward of the forward extremity of said second jack part to aid in the insertion thereof into the front portion of said first plug member.
 6. A connector system according to claim 1 wherein the characteristic impedance of the coaxial cables to which said connector members are to interconnect is substantially 50 ohms while the impedance formed by the spacing of said dielectric inserts are in the range of 62 ohms and the impedance formed by each of said dielectric inserts is in the range of 44 ohms.
 7. A connector system according to claim 1 wherein the volume embraced between said dielectric inserts is substantially 40 per cent and the volume occupied by said dielectric inserts is substantially 60 per cent respectively of the total volume embraced within said connector system between said first internal shoulder of said first plug part and said first internal shoulder of said first jack part when said plug and jack member are fully mated. 